Hemodialysis prolongs life but does not restore normal health in patients with end stage renal disease. Much of the residual illness suffered by these patients is due to retained "uremic" waste solutes which are not adequately removed by conventional dialysis. Efforts are underway to improve solute removal by increasing the frequency and duration of dialysis treatments. But increasing the number of hours/week on dialysis, even if it affords some benefit, would be both burdensome and costly. This proposal will explore the alternate possibility that uremic solute levels can be lowered by dietary manipulations which reduce solute production. Some potentially important uremic solutes are made in the colon, and the investigators have found that the production of these solutes is greatly reduced in people adhering to a vegetarian diet. Based on this preliminary finding, the investigators propose to test the effect of carefully selected dietary manipulations on solute production in hemodialysis patients. Chemical assays will show whether these manipulations reduce production of the colon-derived uremic solutes p- cresol sulfate, indoxyl sulfate, and dimethylamine. Identification of a dietary treatment that reduced solute production would prompt a follow-up study to test the ability of that treatment to improve health outcomes. The investigators believe that over the long term, diet can compliment dialysis to improve patients'health without an increase in dialysis time. PUBLIC HEALTH RELEVANCE: Conventional hemodialysis prolongs life but does not restore normal health in patients with end stage renal disease. Much of the residual illness suffered by these patients is due to retained waste chemicals which are not adequately removed by current dialysis treatment. This study will assess whether the production of these waste chemicals can be reduced by altering the diet. Finding a dietary change that reduces waste chemical production could provide a means for improving the health of dialysis patients without increasing the time they spend on the dialysis machine.